This application relates to German application 197 38 404.8, filed Sep. 3, 1997 in Germany (the priority of which is being claimed), and German application 197 02 084, filed Jan. 22, 1997 in Germany, the disclosures of which are expressly incorporated by reference herein.
The present invention relates to a so-called "plug" type door system with a door panel supported for sequential movement between a door closed position with shapewise interengagement of door frame and door panel structure holding the door panel against lateral opening movements, a door intermediate position with release of the shapewise interengagement, and a door open position with the door panel pivoted and moved to a position conforming to an outside contour of the aircraft body adjacent the door frame.
Known door systems of this type that pivot open (German Patent Document DE 44 13 307 A1), as used in modern passenger aircraft, are of the so-called "plug" type, in other words the door panel, in the completely closed position, is lowered on a curved lifting movement path that matches the external contour of the aircraft with edgewise system hardware integral with the door panel into a shapewise engagement with matching receiving elements fastened to the aircraft structure in the vicinity of the door opening in order to transmit in this fashion the high compressive forces that act on the door panel as a result of the difference in pressure between the cabin interior and exterior pressures during flight, directly and without the interposition of mechanically moved locking elements, from the door panel to the aircraft structure. For opening, the door panel must first be lifted out of shapewise engagement with the receiving elements before it is then pivoted horizontally outward out of the door opening under the control of a supporting and pivoting device that acts between the door panel and the fuselage structure essentially perpendicularly to the lifting movement path, and is then moved in the lateral direction parallel to the outside contour of the aircraft into the completely open position.
In such door systems, the lifting device that consists of the lifting kinematics and the lifting drive is located between the door panel and the supporting and pivoting device, thus ensuring that the pivoting axis of the door panel remains aligned vertical relative to the door frame regardless of the lifting position and thus allows the door panel to move with limited force being applied in the pivoting phase. However, it is difficult to accommodate the lifting device in the narrow installation space between the door panel and the supporting and pivoting device and, since it participates in the pivoting movement of the door panel, the device increases the weight of the door system to be pivoted. In addition, the lifting drive is operated at least by outside energy, namely it is electrically powered, and therefore flexible power supply lines are required between the lifting drive and the door frame, said lines, by comparison to the lifting travel, having to withstand without problems, the pivoting movements that are very large by comparison with the lifting travel, over a plurality of opening and closing cycles.
An improved door system contemplated by the invention provides for problem free lifting movement of the door from the closed position to the intermediate position, followed by an essentially horizontal door panel movement to the open position in a pivoting phase.
According to preferred embodiments of the invention, the lifting movement of the door panel along the curved lifting movement path is effected by a tilting position control on the door frame of the pivoting axis in such fashion that the pivoting axis is aligned vertically relative to the aircraft structure at the end of the opening travel and thus the door panel can be pivoted open and closed essentially in a horizontal direction. On the door frame side, a sufficiently large installation space is normally available for accommodating the tilting position control, and the weight of the door system to be pivoted is significantly reduced by eliminating the lifting device between the door panel and the pivoting device. At the same time, the supply lines for the tilting position control are no longer subjected to the significant pivoting movements of the door panel, thus effectively combating the risk of a functional problem.
As far as a simple design of the pivoting device that contains the pivot axis or axes is concerned, preferred embodiments provide for a supporting arm that is connected rotationally movable with the door panel and with the tilting position control.
In preferred embodiments, the tilting position control of the pivot axis advantageously consists of a mechanical guide that acts between the pivot axis and the door frame, including a motorized tilting position drive, so that additional design simplification and reliable operation of the tilting position control are achieved. In this connection, a spindle drive is advantageously used as the drive, said spindle drive being incorporated into the tilting position kinematics as a linear guiding member and consequently simplifying the latter further. An alternative embodiment of the tilting position control that is especially sturdy in terms of construction, in which nonlinear largely arbitrarily curved guide members approximately in the shape of bent guide rails can also be provided for the tilting position kinematics, provides that the tilting position control contains as a drive, a combined rack and pinion drive curved to match the shape of the guide members. The drive is pneumatically or hydraulically driven but most simply, preferred is electrically driven in especially preferred embodiments.
In order to secure the door panel when it pivots open in the raised lifting position against improper activation of the tilting position drive, the drive is preferably automatically locked when the door panel is pivoted open. In order for the door panel to be lifted at least once out of the "plug" position by the tilting position control if the tilting position drive fails, in certain preferred embodiments of the invention an emergency drive for the tilting position kinematics is provided in addition to the tilting position drive.
In the case of the door systems according to the invention as generally described above, the motor drive of the tilting position control is constructed as a self-locking worm gear in order to prevent that, as the result of vibration or thrust influences, the door panel or door leaf can move by itself out of the fully lowered lifting position and therefore be released from the form-locking engagement with the door-frame-fixed receiving element. Such a lift securing requires a relatively high-expenditure, largely play-free and elasticity-free mechanical coupling of the door panel with the tilting position drive by means of the carrying device and the tilting position control.
In contrast, according to especially preferred embodiments of the invention, the door panel of the door system is secured with respect to the lift by means of a door locking system which is operated in the completely closed position of the door panel and locks this door panel on the door frame independently of the carrying device and the tilting position control.
By means of the direct non-liftable locking of the door panel on the door frame, moving-play-caused or elasticity-caused instabilities of the carrying device and of the tilting position control, including the assigned drive, have no influence on the operational reliability of the door locking system.
In a particularly preferred further development of the invention, the door locking system consists of a locking shaft which is rotatably arranged on the door panel and extends transversely at the level of the locking system operating device essentially along the whole width of the door panel and has locking elements which are fastened on both sides at the respective shaft end and, in the operating position of the door locking system, are rotated in an engagement with corresponding counterelements fixed to the door frame, whereby a constructionally very simple weight-saving further development of the locking system is achieved with a minimal number of component parts.
The operating device of the door locking system according to certain preferred embodiments expediently contains at least one manual lever which is accessible from the interior side of the door panel. Preferably, the door locking system can be manually operated from both door panel sides independently of one another, and, for this purpose, the door panel is provided with a manual lever on the interior side of the door panel and on the exterior side of the door panel, and both manual levers are mutually mechanically uncoupled and are jointly connected to the locking shaft.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.